A beam of neutrons is traveling in the x-direction. Initially, all the spins are up along the z-direction. The neutrons pass through a region in which there is a uniform magnetic field in the y-direction of magnitude B₀ = 1 Tesla. What is the minimum time the neutrons would have to remain in the field to exit it with their spins definitely along z? The magnetic moment of the neutron, a spin 1/2 particle, is = 0.966 10²⁶ J/T (Joules/Tesla).